ST. LOUIS – Astros manager Bo Porter called the media back into his office late Wednesday and delivered the news: Jarred Cosart had a direct ticket to the Show.

After Cosart went out of his way during spring training to say he wanted a spot on the Astros’ opening-day roster, one of the rebuilding organization’s most promising pitching prospects is scheduled to start Friday against Tampa Bay ace lefthander David Price, who won the 2012 American League Cy Young award.

Cosart, 23, went 7-4 with a 3.29 in 18 games (17 starts) for Class AAA Oklahoma City this season. The 6-foot-3, 180-pound righthander struck out 93, allowed 74 hits and walked 50 in 93 innings.

Cosart is ranked as the Astros’ No. 7 overall prospect by Baseball America. The former Philadelphia Phillies prospect and League City native has some of the best stuff and one of the most lively arms in the Astros’ organization. If he succeeds, he could pair with 22-year-old righthander Jordan Lyles in the club’s rotation during future years.

“He’s got a great arm. And I think as the season went on he started realizing how to use it,” said Astros rookie outfielder Marc Krauss, a recent OKC teammate of Cosart’s.

Lefthanders Dallas Keuchel and Erik Bedard will follow Cosart against the Rays during the Astros’ final series before the All-Star break.

Cosart went 0-1 with an 8.22 ERA during spring training. He started strong but struggled with his command and control. A key March 4 start against Detroit saw the righty give up four hits, three runs and four walks in just two innings.

“I talked to the (Oklahoma City) coaches the other day. He still has a lot to learn,” Astros pitching coach Doug Brocail said. “More so, from what I’ve been told, physically he’s ready. … I’m looking forward to seeing what the kid has. I know his arm’s incredible. But I want what’s above the shoulders to go with it.”

Cosart’s promotion has multiple effects. It brings more clarity to Harrell’s demotion, puts the remainder of the Astros’ starters on notice, gives the club a possible out if one or more starting pitchers are traded – Bud Norris, Harrell and Bedard are candidates – and represents the next wave of the club’s rebuild.

With Cosart called up, shortstop prospect Jonathan Villar could join the team in August, while a September promotion for center fielder George Springer is an increasing possibility.

Baseball America’s scouting report on Cosart: Cosart has a live, quick arm that produces a hard sinker that sits at 94-97 mph and touched 99 in the AFL. His fastball has excellent life down in the zone, which produces plenty of ground balls but makes the pitch tough to control. He excels at keeping the ball in the park, and he nearly got as many double plays (18) as he allowed extra-base hits (26) in 2012. Cosart throws his curveball with power, reaching 81-82 mph with good shape, and his solid straight changeup plays off his fastball well. Better command of his curveball would produce the strikeouts expected of a pitcher with such electric stuff.

Twitter: ChronAstros

Photo: Dilip Vishwanat / Getty Images

Image 1of/28

Caption

Close

Image 1 of 28

July 10: Cardinals 5, Astros 4

J.D. Martinez is tagged out at home by Tony Cruz of the Cardinals.

July 10: Cardinals 5, Astros 4

J.D. Martinez is tagged out at home by Tony Cruz of the Cardinals.

Photo: Dilip Vishwanat / Getty Images

Image 2 of 28

Matt Adams hits an RBI single against the Astros in the second inning.

Matt Adams hits an RBI single against the Astros in the second inning.

Photo: Dilip Vishwanat / Getty Images

Image 3 of 28

Jake Elmore turns a double play over Matt Adams.

Jake Elmore turns a double play over Matt Adams.

Photo: Dilip Vishwanat / Getty Images

Image 4 of 28

J.D. Martinez hits an RBI single.

J.D. Martinez hits an RBI single.

Photo: Dilip Vishwanat / Getty Images

Image 5 of 28

Matt Holliday follows through on a two-RBI single.

Matt Holliday follows through on a two-RBI single.

Photo: Tom Gannam / Associated Press

Image 6 of 28

Cardinals starting pitcher Shelby Miller delivers in the first inning.

Cardinals starting pitcher Shelby Miller delivers in the first inning.

Photo: Tom Gannam / Associated Press

Image 7 of 28

Matt Carpenter, right, rounds the bases after hitting a two-run home run in the seventh inning.

Matt Carpenter, right, rounds the bases after hitting a two-run home run in the seventh inning.

Photo: Chris Lee / Associated Press

Image 8 of 28

Matt Holliday recoils from an inside pitch.

Matt Holliday recoils from an inside pitch.

Photo: Tom Gannam / Associated Press

Image 9 of 28

Yadier Molina reacts after striking out.

Yadier Molina reacts after striking out.

Photo: Tom Gannam / Associated Press

Image 10 of 28

Astros starting pitcher Jordan Lyles delivers.

Astros starting pitcher Jordan Lyles delivers.

Photo: TOM GANNAM / Associated Press

Image 11 of 28

Matt Carpenter follows through on a two-run home run.

Matt Carpenter follows through on a two-run home run.

Photo: Tom Gannam / Associated Press

Image 12 of 28

Astros relief pitcher Wesley Wright reacts after giving up a two-run home run to Matt Carpenter.

Astros relief pitcher Wesley Wright reacts after giving up a two-run home run to Matt Carpenter.

Photo: Tom Gannam / Associated Press

Image 13 of 28

Chris Carter celebrates with Brett Wallace as he crosses the plate after hitting a solo home run.

Chris Carter celebrates with Brett Wallace as he crosses the plate after hitting a solo home run.

Photo: TOM GANNAM / Associated Press

Image 14 of 28

Jose Altuve slides safely into home.

Jose Altuve slides safely into home.

Photo: Tom Gannam / Associated Press

Image 15 of 28

J.D. Martinez catches a foul ball.

J.D. Martinez catches a foul ball.

Photo: Tom Gannam / Associated Press

Image 16 of 28

Astros catcher Jason Castro sets to throw out Allen Craig at first.

Astros catcher Jason Castro sets to throw out Allen Craig at first.

Photo: Tom Gannam / Associated Press

Image 17 of 28

Jason Castro returns to the dugout after striking out.

Jason Castro returns to the dugout after striking out.

Photo: Chris Lee / McClatchy-Tribune News Service

Image 18 of 28

July 9: Cardinals 9, Astros 5

Bud Norris of the Astros delivers a pitch to the Cardinals.

July 9: Cardinals 9, Astros 5

Bud Norris of the Astros delivers a pitch to the Cardinals.

Photo: Tom Gannam / Associated Press

Image 19 of 28

Astros starting pitcher Bud Norris regroups after giving up a solo home run to Matt Holliday of the Cardinals.

Astros starting pitcher Bud Norris regroups after giving up a solo home run to Matt Holliday of the Cardinals.

Photo: Tom Gannam / Associated Press

Image 20 of 28

Astros left fielder Marc Krauss collides with the wall as Cardinals fans reach for a home run hit by Matt Holliday in the first inning.

Astros left fielder Marc Krauss collides with the wall as Cardinals fans reach for a home run hit by Matt Holliday in the first inning.

Photo: Tom Gannam / Associated Press

Image 21 of 28

Astros pitcher Bud Norris delivers a throw to the Cardinals.

Astros pitcher Bud Norris delivers a throw to the Cardinals.

Photo: Dilip Vishwanat / Getty Images

Image 22 of 28

Astros pitcher Bud Norris delivers a throw to the Cardinals.

Astros pitcher Bud Norris delivers a throw to the Cardinals.

Photo: Dilip Vishwanat / Getty Images

Image 23 of 28

David Freese of the Cardinals is tagged out at home by Astros catcher Jason Castro as he tried to score from third during the fourth inning.

David Freese of the Cardinals is tagged out at home by Astros catcher Jason Castro as he tried to score from third during the fourth inning.

Photo: Tom Gannam / Associated Press

Image 24 of 28

Cardinals starting pitcher Adam Wainwright pitches in the first inning against the Astros.

Cardinals starting pitcher Adam Wainwright pitches in the first inning against the Astros.

Photo: Tom Gannam / Associated Press

Image 25 of 28

J.D. Martinez of the Astros attempts to field a deep fly ball against the Cardinals during the second inning.

J.D. Martinez of the Astros attempts to field a deep fly ball against the Cardinals during the second inning.

Photo: Dilip Vishwanat / Getty Images

Image 26 of 28

Astros starting pitcher Bud Norris takes a practice pitch while being observed by a trainer and manager Bo Porter in the second inning.

Astros starting pitcher Bud Norris takes a practice pitch while being observed by a trainer and manager Bo Porter in the second inning.

Photo: Chris Lee / t. Louis Post-Dispatch/MCT

Image 27 of 28

Home plate umpire Mark Wegner warns the Cardinals bench after Astros Jason Castro was hit by a pitch in the sixth inning.

Home plate umpire Mark Wegner warns the Cardinals bench after Astros Jason Castro was hit by a pitch in the sixth inning.